[AK]

I didn´t get much response in the technical forum so I´m reposting it here:

I´m planning to remap my 320d, BUT before I do that I need to find out if I should put on an Eisenmann exhaust (i.e. muffler and twin tips, picture below, and link: http://************/3bxv9k) or not. The Eisenmann exhaust will have less back pressure than the OEM, so one of the parameters when remapping will be changed, meaning I need to put it on BEFORE the remap right? But how will it affect the power output and torque of the car when remapped? Will it give better results than if remapped with the OEM system or just different results, say less torque but more hp, or what? And what about the rev limit, will it rev higher with the Eisenmann system?

[Cafe.Racer]

Honestly - I'd expect it to make practically no difference, EVEN if you were going for a full custom map.

I think these ECU's are adaptive anyway, so it'll cope with changing a back box.

[AK]

Yes that´s what I´ve been thinking as well. The ECU somehow adapts, but isn´t changing the back pressure a bit too much to adapt to?

[dxb335d]

cant see if affecting anything apart from the sound, if it was a full system then maybe!

let us know how the car feels after the map

Carl

[ChrisMWard]

I would be surprised if there was any significant back pressure with either back box. Back pressure is caused by silencing. Diesel engines make less exhaust noise than equivalent petrol engines, with more of the fuel turned to power and less wasted as heat and noise, therefore less silencing is required. Adding a turbo, or rotary muffler as our American cousins call them, also removes a lot of the exhaust noise. Again manufacturers try and remove any back pressure in the system downstream of the turbo as this will promote lag.

Regards

Chris

[dxb335d]

yeah turbo cars are quieter in general, i have an old Fiesta rs turbo in storage somewhere, which is alot quieter than a N/A engine of the same type, (CVH) even with a stainless steel exhaust, its a much deeper sound but not so loud as such.

I would imagine a e46 m3 would be much louder than a 335i for instance!


i have always loved turbocharged cars as they can be tuned immensely well and make big power gains. I was in the ford scene for a while, and so many people were tuning up cosworths so heavily it was amazing

some doing 0-62 in under 3 secs, and one which has now topped a GPS verified 206mph in a sierra cossie, a very brave man i say.


Do not know much about diesel turbo tuning, i know same rules apply (in principle) but how far can you go as the diesel engine in general is a high compression engine with relaively low boost, the opposite to a petrol turbo engine!

i mean a re-map on the 335d will give a good 340-350bhp and 530 ib ft

but what would be the next stage?? a bigger intercooler to run even more boost??

370-380bhp possible???

Carl

[ChrisMWard]

The 335d engine already uses a lot of boost, I've heard figures of 2.65 bar (probably not right) or 26psi (sounds more like it).

I'm sure normal turbo tuning practice would apply though, larger intercooler, larger secondary turbo, exhaust, remapping. A lot of development and money would have to be thrown at it no doubt.

Regards

Chris

[Patman]

Originally Posted by AK

I didn´t get much response in the technical forum so I´m reposting it here:

I´m planning to remap my 320d

Hi !

i would be interested in the result of your remap, i have myself a 320d too, and i am hesitating to do it ...

[Paul330d]

Don't hesitate, do it! I found a very professional company in Belgium that did my 330d last September (www.kempower.be).

[AK]

Hello Paul! I´ve been away from the forum for a while, but now I´m back as you can see. Yes Kempower is it! When I do the remap it will be with Kempower I´ve been in contact with them. Just need to find a date for the appointment. But then I saw this Eisenmann exhaust for the 320d, see above post, and I wondered if I should put it on, and if I do I probably have to put it on before the remap. But I´m not 100% sure if it will have a positive effect on the remap or not. If I end up losing torque compared to a remap with the OEM exhaust, it doesn´t seem like a good idea to put on. But what about the redline? Will the less back pressure give a higher rev limit?

[ChrisMWard]

Back pressure will not effect the red line of a diesel (well not in the case of modern automotive applications). The revability of a diesel engine is governed primarily by the burn speed or flame travel of the fuel. The injection timing can only be advanced so far to overcome this. Great strides have been made with the current crop of engines and more is to come with the ever increasing use of electronic control.

Regards

Chris

[dxb335d]

Originally Posted by ChrisMWard

The 335d engine already uses a lot of boost, I've heard figures of 2.65 bar (probably not right) or 26psi (sounds more like it).

I'm sure normal turbo tuning practice would apply though, larger intercooler, larger secondary turbo, exhaust, remapping. A lot of development and money would have to be thrown at it no doubt.

Regards

Chris

26psi??? cant believe that... thats ALOT of boost

as a general rule diesels run small turbos and small amounts of boost to combat lag and be responsive, now that may differ with our twin turbo 335d i am not 100% sure

the diesel engine is a high compression engine, which leads onto the reason why low boost quick to spool up turbo's are used with minimal boost

petrol turbo engines tend to be of a lower compression depending on the application, (rally car run very high compression and 30+psi of boost, with a restrictor to create copious amounts of torque and limited to 300bhp) but most roaD cars which are turboed run lower compression than a N/A engine.

for instance, a escort rs cosworth (4wd 2.0 16v turbo hero from the early nineties, won monte carlo rally 1994 and mille milglia 1996 etc)
and one of my favourite cars of all time







(think we all know who this chap is )



produces 227bhp in standard trim, with a t3 turbo.

so with..

Standard engine and turbo =
Std approx 9psi held.

Stage 1 = 16held. 280-290bhp

Stage 2 = 23 held 310-330bhp

and depending on what spec head etc can make 400bhp with 25psi, thats a relatively low comp engine.

would have thought a straight six twin turbo diesel would be running only 12-15psi to produce 285bhp but i could be compeltely wrong?

carl

[Insider]

Originally Posted by dxb335d

Do not know much about diesel turbo tuning, i know same rules apply (in principle) but how far can you go as the diesel engine in general is a high compression engine with relaively low boost, the opposite to a petrol turbo engine!

Carl

Actually the above statement is totally wrong. Diesel's are the high-boost engines, petrol low-boost. The 335i has max boost of 8.5 psi, the 335D has max boost of 26psi. Diesel's work off heat, and need high compression and high turbo boost to generate lots of heat, this is how the fuel is ignited. The petrol relies on a spark plug so does not need the heat (would cause detonation, not a problem with diesel). Diesel fuel is very slow burning, so diesels by nature can't rev very high, thus their high torque, low horsepower character.

[dxb335d]

so how come on a petrol engine? to run more boost you need to lower compression??

high compression + turbo boost, surely = detonation

[dxb335d]

so what boost do you think a 335d needs to run to produce the re-mapped 350bhp??

and are you sure with facts that it runs 26psi?

thanks

carl

[Insider]

Originally Posted by dxb335d

so how come on a petrol engine? to run more boost you need to lower compression??

high compression + turbo boost, surely = detonation

Becuase high compression on a petrol will lead to detonation. This occurs when the fuel is ignated before it is suppose to be ignited. The fuel with the petrol is supposed to be ignited with the spark plug, if there is too much heat (high compression will cause this) then you get detonation. With the diesel this is not a problem because there is not spark plug, the diesel fuel is suppose to be ignited by heat, that is why you can have high compression in the diesl along with high boost. It's good for it The petrol engine must have relatively low compression and turbo boost to prevent too much heat.

[Insider]

Originally Posted by dxb335d

so what boost do you think a 335d needs to run to produce the re-mapped 350bhp??

and are you sure with facts that it runs 26psi?

thanks

carl

I am not sure how much boost it would need. My best guess would be 32+psi. The turbo's can only provide so much boost. I am pretty sure I read somewhere the stock boost on the 335D is around 26 psi. Sounds about right as Mercedes diesels are up around 22psi as well.

[dxb335d]

right ok, thanks for your info.

Also do you think the turbos are upto the job of running the required boost to make 350bhp after a re-map?

carl

[ChrisMWard]

The Audi R10 that just won the Le Man 24hr runs 42psi of boost into its V12 diesel to make 650BHP and 1100 Nm of turnies.

Regards

Chris

[bmw330d]

I have just had a remap done on my 330d. I asked the question about exhausts and filters and all of the mapping companies I spoke to said no tweaking of the map was required, all that is needed is to disconnect the battery for half an hour and when you reconnect the car adapts to the changes.

[Insider]

Originally Posted by dxb335d

right ok, thanks for your info.

Also do you think the turbos are upto the job of running the required boost to make 350bhp after a re-map?

carl

I think the turbo's in the 335d will be fine and up to the task. But really, only time will tell if this is indeed the case.

[dxb335d]

right i see.

can you tell im used to turbo petrol engines lol


all talk of det and it dosent even matter with a densel


doughnut lol


carl